Hey, That's Not Supposed to Smoke...

Todays blog posting revolves around an “incident” that happened in the shop on Thursday.

In the interest of presenting the story in painfully slow motion (my usual mode of troubleshooting), I’ve decided to present you all with a question and a series of clues that document my train of thought through the “incident”. I find that when things go wrong in the shop, revisiting this train of thought is a great way to prevent that particular thing from happening again.

Spoiler Alert: No woodworkers were harmed during the “incident” - neither was the building (or the saw). How’s that for heightening the drama? Winking

The Take Home Message answers the Question: What tool will I use to complete my cut and why? Anything else to do in future?

My Train of Thought:

  • Nice day to make some leg blanks for upcoming chair project. [No problems so far...]
  • Next Rip Cut - 12/4 walnut dimensioned to 2 7/8” thickness. [Note: with a 10” blade, that’s about max for my table saw]
  • Good thing the board appears to be stable. [I now know that it had significant internal stresses]
  • Raise the blade to max and start the cut. Careful that the board doesn’t lift up off the table with that much blade in the work. [3” into the cut, everything is fine]

For those of you who think I’m about to describe a kick back, this is where the plot takes a twist (you see, I was paying special focused attention because I thought kick back was the most likely danger, too).

  • We are about 4” into the cut when II notice: Hmmm, lots of sawdust in the air [Dust Collector is on]
  • I should mention my dust collection is less than stellar at my table saw [It’s farthest from the Dust Collector in the shop]
  • Suddenly the cut starts to bog down...
  • Quickly verify the saw blade is exiting the top of the board [It does, but only by about 5/16” - I had ripped an edge earlier, and got a clean cut, so I was sure the blade height was not the issue]
  • It has been awhile since I cleaned or sharpened this blade. It might be time to do that.
  • Next, the internal stresses in the board caused the kerf to start to close around the saw blade. [So that was the main problem]
  • Luckily, the cut had reached the splitter, which did its job and prevented the kick back. [Yeah! Go Splitter!]
  • This particular board had enough pressure to tightly clamp the spitter, making it almost impossible to feed with ordinary pressure. [The only kind of pressure you want to use with a table saw]
  • Thus, my forward feed rate dropped to almost nothing. The cut begins to smoke.... [Did I mention I hadn’t cleaned out the table saw cabinet in a bit - as it turns out, a very long bit...]

As far as identifying the “incident”, you should now be getting “warmer”. From here, the pace of things speeds up a bit...

  • While the spiltter kept the board from being thrown back, the cut was building up a lot of heat around the saw blade [More smoke - still convinced the smoke came from the dirty saw blade and stationary bit of wood]
  • Not liking the way the cut was going (i.e. nowhere), or the smoke, or the binding, I shut the saw down safely.
  • Now I can relax...
  • Dropped the blade so I could remove the board from where it was binding the splitter...Huh, there’s still smoke. Must have gotten really hot...
  • Removed the board (it took a couple of tugs) and turned around to place troublesome board on the work bench [Still in relaxed mode]
  • Turn back to the saw...which is still smoking...in fact quantity of smoke is increasing rapidly..in fact, that looks like a little mini chimney coming out from the table saw insert... [Note: No longer in relaxed mode!]
  • Final thought - table saws are not supposed to make a crackling popping noise - My Table Saw is Trying to Catch Fire!

The Immediate Actions required:

  • Put the Fire Out! [Luckily, I tend to leave large water glasses around the shop and had 2 big ones nearby]
  • Dumped the water in the saw cabinet [And even managed to avoid soaking the trunion - that’s keeping one’s head under pressure Winking]
  • Ran for my fire extinguisher [it’s a powder model, so I really didn’t want to use it unless I had to - the clean up would have been horrific]
  • Ready to blast the interior of the saw cabinet [Luckily, the smoke is looking more steam-like now...]
  • Fire is Out. Whew. Didn’t see that one coming!

Thoughts for the Future:

  • When you have poor dust collection, you’d better clean out the saw more frequently [made it a monthly reminder on my calender]
    • The root of the problem (after sucking 8” of saw dust out of the cabinet was that a 7” strip of material (less the 1/32” thick) had seated itself directly in the outlet housing where my DC connects. That caused the sawdust to plug the outlet.
    • I got used to reduced quality of dust collection slowly over time, and didn’t realize I had an unsafe condition which built up over time.
  • Why was I cutting 12/4 stock on a 10” saw blade? Lazy Lazy Lazy. I knew the table saw would make the one cut I needed faster than the band saw (I would have had to change the blade on the band saw, first). So, I pushed the envelope on the saw and the saw bit back.
    • It seems to me I heard of a website that puts out a podcast called iWoodWork. After viewing the show list, I recommend reviewing Episode 2 - The Bandsaw. It talks about using the band saw to mill lumber that would be unsafe or unwieldy on the table saw. Maybe I should have practiced what I preached. Winking

So Take Home Message is,

“What tool will I use to complete the cut”? : The Bandsaw!
  • Once I had ripped the 2 legs apart, I could then have returned to the table saw for the edge clean up (or even the thickness planer and jointer).

“Why”: It’s the safer of the two tools when your depth of cut starts to approach 3” (let’s call it 2 1/2&rdquoWinking.

“Anything Else”?
  • Do routine saw maintenance on a more frequent basis.
  • Also, don’t place the water cooler in front of the fire extinguisher - makes things awkward in an emergency (the only time you really need said fire extinguisher...).
  • When it comes to convenience vs. safety, I might want to come down on the side of safety next time...

Well, I got the saw cleaned up, did the maintenance required, and I’ve cut the peice safely on the bandsaw. All in all, I got off cheap. I wanted to go into this in such great detail, because this sort of thing can happen at any moment - and sometimes does.

Keep Safe, Everybody!